When the US Naval Academy contacted my son a few months ago, he was told that he wouldn't need a congressman or senator to provide a nomination, that the baseball offer would take care of that part. This would help simplify the process, but he still would be subject to the rest of the admissions process.
Also, recruits need to be well-informed regarding their obligation after college ends. The coach did state that if son got drafted after his JR year, the Navy would let him play pro ball, but then he would need to come back and fulfill his obligation. Its an important and serious commitment. I only know of one basketball player that somehow was relieved of his obligation.
It takes a special kid to make this kind of decision at age 17. Often these are the kids have dreamed their whole life of these schools, and thank goodness for them! The average (somewhat spoiled) teenager might not make it through the first year!